<?php

class Silk_Zgb_Block_Renderer_Total extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract
{
    /**
     * @param Varien_Object $row
     * @return mixed
     */
    public function render(Varien_Object $row)
    {
        //$data =  $row->getData();
        $subtotal = $row->getSubtotal();
        $totalRefunded = $row->getTotalRefunded() ?: 0;

        return Mage::helper('core')->currency($subtotal - $totalRefunded, true, false);
    }
}